Hepatitis E virus: the need for improved testing

Hepatitis E virus (HEV) is a single-stranded positive-sense RNA virus and is a leading cause of acute viral hepatitis worldwide. The infection is usually asymptomatic or self-limiting in the general population. Currently, eight distinct genotypes of HEV have been classified but only one serotype has been described. Four main genotype 1-4 are known to be the main threat to humans. Genotypes 1 and 2 are restricted to human and mainly transmitted through contaminated water in low income countries. They can cause acute hepatitis, including severe forms in patients with pre‐existing liver disease and in pregnant women Genotypes 3 and 4 are zoonotic and have been identified in a wide spectrum of hosts, including human, swine, wild boar, rabbit, deer. Infection with genotypes 3 and 4 can become chronic in immunocompromised patients. Extra‐hepatic manifestations, especially neurological and renal diseases, have also been described. HEV infection is diagnosed by laboratory testing since its clinical presentation does not differ from other pathogens causing hepatitis. The detection of IgM and IgG antibodies and virus RNA are used to confirm HEV infection. In immunocompetent individuals, IgM detection is essential because there is a narrow window in which HEV RNA can be detected in serum or faeces during the acute phase of the disease. Currently, there are various commercially available serological anti-HEV diagnostic tests. Unfortunately, a widespread variability of assay sensitivities and specificities has complicated the understanding of HEV spread worldwide. For instance, the use of anti-HEV IgG ELISA kits from different manufacturers has a substantial impact on the global estimation of anti-HEV IgG seroprevalence.

 

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